Effect of Gamma Irradiation on the Molecular Composition of Semolina Soluble Protein Fractions

The effect of gamma irradiation (0, 0.25, 1, 2.5, 5, 10 and 90 kGy) on the total protein content as well as the amino acid composition and electrophoretic patterns of the soluble proteins of semolina stored for 6 months was investigated. The protein content of the semolina sample irradiated with the high dose of 90kGy( 10.2 % as is) was significantly ( P 0.05) lower than that of any of the samples irradiated with 10kGy or lower( 10.9- 10.7 % as is). The latter doses had no significant ( P 0.05) effect on this variable. The amino acid content of the irradiated semolina was influenced , yet irregularly, by the irradiation dose. In general, there was an increase of tyrosine and methionine accompanied with a decrease in lysine and phenylalanine upon increasing the irradiation dose in the range of 0 to 10 kGy. On the other hand, the 90 kGy dose resulted in a drastic decrease in total amino acids as analyzed with this procedure. Electrophoresis (SDS-PAGE) separation of soluble protein fractions from semolina showed that the intensity of the bands and their numbers decreased substantially upon increasing the irradiation dose above 5 kGy